Sylvania



June 2, 1931. T. KING ET AL 1,308,557

GAS BOILER v I Filed May 21. 1928 2 Sheets-Sheet 1 June 2, 1931. v K|NG ET AL 1,808,557

GAS BOILER Filed May 21, 1928 2 Sheets-Sheet 2 Patented June 2, 1931 UNITED STATES PATENT OFFICE" THOMSON KING, OF POTTSTOVTN, AND DANIEL G. BURKER'I, OF B OYERTOWN, PENN- SYLVANIA, ASSIGNORS TO THE PEERLESS HEATER, COMPANY, OF BOYERTOWN, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA V I GAS BOILER Application filed. May 21,

Our inventionrelates particularly to a gaseous fuel mixer which is of general utility, but which may be advantageously employed in a gas fired water heater or boiler of the type wherein the burner is secluded in a combustion chamber, which is substantially closed except for inlets supplying primary airthru burner, only so long as the residual fluid pressure in the conduits for the combustible mixture of air and gas leading to said main burner is suflicient to force the mixture thru the burner jets. However, the upward draft of the products of combustion, which maintains the confined atmosphere around the burner at a pressure slightly less than the outer atmosphere, quickly reduces the fluid pressure at said burner until the mixture escaping' thru the burner jets diminishes in combustibility, the flames lower to the jet openings, and are propagated thru said openings to the richer mixture inside of the burner, causing an instantaneous explosion of the mixture confined in the burner and the conduits leading thereto which, altho of insuflicient force to damage the burner or heater structure, produces a noise which is startling, and consequently highly objectionable to the occupants of the building in which the burner is located.

. Therefore, it is the object and effect of our improvement to prevent, or at least substan tially decrease, any audible manifestation of such explosion of the combustible mixture after the gas supply pressure is shut ofi. To

that end, our invention consists in so constructing and arranging the gaseous fuel mix-; ing elements of such a burner that, when the main supply of gas is shut olf, the residue of such mixture in the burner and the conduits 1928,. Serial No. 279,532.

leading thereto is gradually consumed above the burner jet openings, without any' flash back of the burner flames thru said openings. As hereinafter described, our inventlon includes a gaseous fuel mixer in communication with the burner for such aheater as above described; wherein the primary air suppl ed for mixture with the gas, insteadof being introduced to the gas stream flowing in the mixer, in the samedirection as the 'flowof gas, is introduced in the opposite direction, and preferably from, or in communication with, the confined atmosphere surrounding the burner jet openings; so thatwhen the nor mal gas stream, which by its pressure-normally introduces a forcible inflowof air to the burner to mix with the gas, is shut oif, llhflll flowing thru the mixer. to the burner is subjected to the same tension as the gaseous mlxture flowing out thru the jet openings.

In other words, the draft in the confined at-i mosphere surrounding the burner is effective to prevent such rapid introduction of air to the burner as to permit the formation of an explosive mixture within the burner. quently, the rich gaseous mixture left in the burner and its conduits when the gas supply is suddenly shut oif, is slowly consumed at the burner jet openings without flash back or explosion. I

'Altho it is preferable that all ofthe pri mary air supplied to our improved mixer shall be. drawn from the confined atmosphere in which the mixture is consumed, municipal supplies 'of fuel gas vary extensively in Brit ish thermal units; For instance such gas in Denver, Colorado, averages 320 such units; at Bulfalo, New York, 800 such units; and in Northwest Pennsylvania 1200 such units. Therefore, it is practically impossible. to', form a mixer with invariableair inlets adapting it to mix the proper amount of air with gas of suchvarying richness. Therefore, we

prefer to provide our mixer with adjustable means'to inlet air in .variable quantities, from the outer atmosphere, as hereinafter described. r 1 Our invention includesitheyarious novel features of construction and arrangement hereinafter more definitely specified.

In said drawings: Fig. I is a vertical sectional view of a gas boiler embodying our improvements. 7

Fig. II is a longitudinal sectional View of the gaseous fuel mixer indicated at the lower right hand corner of Fig. I.

Fig. III is a cross sectional view of the said mixer, taken on the line 111,111 in- Fig. II.

Fig. IV is an outer end elevation of the mixer shown in Figs. I and II, as seen from the right hand end thereof, and shows the valve means for variably controlling the sup ply of outer atmospheric air to the mixer.

Referring to the Fig. I; the gasboil'er com prises the hollow base casing 1 inclosing the combustion chamber 2. The main burner '3 which is a hollow castinghaving a series. burner jet orifices 4 in its upper wall thru which the gaseous mixture is supplied to'the names '5, is conveniently supported in stationary position in said combustion chamber 2, upon the cross bar '6. Said main burner is conveniently lighted by the pilot burner 8' supplied with gas thru the conduit 9. The

. arrangement is preferably such that said pilot burner is not controlled by "any thermostatic means which may be employed to control the'supply of gas to the main burner thru the conduit 10; so that the pilot humor 8 may remain lighted when the flames 5 are extinguished at the main burner. U

Asindjieated in Fig. I; the is delivered from the conduit 10, to supply the main burner "3, thru the fitting" 12, containing the stop cook 13, by which the flow of gas may be manually controlled. Said fitting 12 has the gas orifice nozzle 14 which determines the volume of gas in the stream emittedthru said ffitting 12. Said nozzle 14 is in axial al'ineiment with the Venturi tube 15 leading to said main burner "3, and it is to be LlIIClQI'- stood that the arrangement is such that the forcible issuance of the stream of gas thru said nozzle '14 into said tube 15 normally creates a partial vacuum at the flaring mouth 16 of said tube, inducing the flow of air'into mixture with the gas stream.

, However, it is characteristic of our invention that the mixer casing 18is'so constructed .z: and arranged that altho outer atmospheric.

air may be admitted thereto thru "openings 19 at its outer face under control otthe rota ry valvedisk 20 'whi'ch has openings 21 therein, which may be brought into registry with-said openings 19;jsaid valvedisk'2O may be set "in such rotary position as to close said. openings 19, as indicated in Fig. IV. 'Sai'd valve disk 20, may be secured in any position withinits range of rotary adjustment,

by'me'ans oi the nut 22 which is in engagement with the screw thread "23 'on the said fitting 12.

An essential feature of our invention is such "construction and arrangement of the mixer 18'that the primary air may be introduced in a direction opposite to that of the flow of the gas supply hereto, and preferably from the interior of the combustion chamber 2. For that purpose; we provide the mixer 18 with the cylindrical tubular extension 25 which is adapted to be held in spaced relation with the perimeter of the mouth end 16 of the Venturi tube 15, by inwardly extend-.

15; to precisely determine the relative position of the gas nozzle 14:, with reference tothe venturi. Said tubular extension 25- of the mixer casing 18 extends thru the side wallof the boiler base casing 1, and the joint between said extension and wall may be sealed by any convenient means, such as plastic cement. v

The purpose and eilect of thus forming a pluralityof air passages 27 in concentricrela'tion with the axis of the Venturi tube 15 is not only to insure the uniform mixture of the primary air with the stream of gas directed thru said'no'zzle 1-4, as above described, but to insure the uniform and gradual :dilution of the rich mixture remaining in the mixer casing 18 and said tube 15 when the gas is shut on and the induction of the air from the combustion chamber to said tube" is efiected solely by the combustion of the radually diluted mixture in the flames 5 of the burner 3'. Such construction and arrangement'were' adopted'only after we had determined the utility and. advantages thereof by considerable experimentation. It

may be observed, with reference to Fig. III,

that the ribs 26 which separate the circular series ofair passages 27 are of considerable circumferential extent, and such extent was determined in the course of such experiments to be necessary to the proper distribution of the air with respect to the initial 'end 16' of the Venturi tube 15. That is to say, when said ribs 26' were reduced to the miniinumcircu-mferential extent necessary to merely hold the Venturi tube in concentric relation withthe tubular casing extension 25'; the -conse-' quent circumlierential enlargement of said air passages 27 practically nullified the direct1onal and uniformly distributing effect of said passages which is characteristic of the proportion shown.

The effect of the construction aind arrange-r V ment above described is that the primary air introduced to mix with the stream of gas flowing to thefVenturi tube 1-5 thru the nozzle 14:, is entirely-drawn from the secluded atm osphere in the combustion chamber 2, and

isintroduced to the mixing chamber '29:

the outer atmosphere thru said openings 19 in the mixer casing 18, if the gas is so rich as to require such extra dilution to produce a combustible mixture. In any event, the construction, arrangement and adjustment are such that when the gas supply stream issuing from the orifice nozzle 14 is suddenly shut off, (by the thermostatic means above contemplated, or otherwise), instead of thereafter rapidly diluting the body of rich gas in the mixer 14, tube 15, and burner 3, and thus forming an explosive mixture as heretofore; the rich residual gas is thereafter only slightly diluted by mixture with suflicient air from the confined atmosphere of the combustion chamber to replace the rich mixture which slowly issues from the burner jets and is slowly consumed without any audible manifestation of its combustion.

We have found it convenient to show, in Fig. I, in cooperative relation with the gas burner above described, a water-boiler which may include a series of hollow castiron sections 30, with flue openings 31 therethru, and connected by water conduits 32 and 33 respectively at the bottom and top thereof, said sections being held together in cooperative relation by bolts 34 and 35, extending,

thru lugs 36 and 37, on the sections 30. Said sections 30 are thicker at their side edges than intermediate thereof, and have spacing lugs 38 and 39, insuring that when they are clamped together by said bolts 34 and 35, with cement between said edges, they shall be in such spaced relation as to form flue passages extending vertically between said sections, and in communication with the flue chamber 40 within the casing 41 at the top of the boiler structure, which casing has the flue vent 42 leading to a chimney. In such a boiler, each section 30 preferably has a main burner 3, local thereto.

Such a boiler structure is conveniently heat insulated by the outer casing 44, and may be provided with the usual water fitting 46, carrying the gage 47 a pressure regulator 48, etc. For instance, the auxiliary air inlet 50 in said base casing 1 may be provided with the valve 51 by which it is normally closed, when said valve 51 is upheld by the chain 52 leading to thermostatic means which is operative at abnormal temperature to release said chain and permit said valve 51 to be opened by the weight 53.

However, our improved gaseous fuel mixing device may be advantageously employed latter, or the form of combustion chamber in which it is operated. For instance, such a mixer may be advantageously used with a burner in the oven of an ordinary kitchen range, or other hot air chamber. 7

' Therefore, we do not desire to limit ourselves to the precise construction, arrangement or method of operation above described, as various modifications may be made therein without departing from the essential features of our invention as defined in the appended claims. 4

We claim:

1. In a gaseous fuel mixer; the combination with a burner; of a combustion chamber, seclucling said burner from the outer atmosphere; a gas orifice nozzle arranged to direct gas in a stream; a mixer casing inclosing said nozzle and forming a mixing chamber having an outlet for said mixture; and means for forming an air passage, arranged to introduce primary air to said mixing chamber in a direction opposite to said gas stream, and between said stream and outlet; whereby mixture of said gas and air is efiected before reaching said outlet; wherein said mixer casing is located outside of said combustion chamber, but the primary air is drawn therein solely from said combustion chamber.

2. A structure as in claim 1, wherein a plurality of such air passages are separately disposed parallel with, but in radially and circumferentially spaced relation to, the axis of said nozzle. 7

3. A structure as in claim 1; wherein a circular series of parallel air passages is disposed in coaxial relation with said nozzle; whereby the air from said combustion chamher is divided in a plurality of small streams in uniformly spaced relation with the axis of the gas nozzle before mixing with the gas, and uniform mixture of the gas and air thereby assured.

4. A structure as in claim 1, wherein the outlet is a Venturi tube in coaxial relation with said gas nozzle, and a circular series of such air passages is formed around said tube; 31

whereby, the air from-said combustion chamber is divided in a plurality of small streams in uniformly spaced relation with the axis of the Venturi tube before mixing with the gas,

and uniform mixture of the gas and air there- 1 by assured.

5. A structure as in claim 1 also having means arranged to admit primary air in the same directionas the gas stream.

6. The combination with a Venturi tube;

of a mixer casing inclosing the initial end of said tube; and means holding said tube and casing in coaxial spaced relation, including a circumferential series of ribs between them;

said ribs forming a circular series of separate air passages between said tube and casingg'wherein said endoflthe Venturi tube terminates in a plane at right angles to its axis and saidribs have respective abutment-s with faces extendingin a plane at right angles to the axis of saidcasing and in contact with said tube end; whereby said tube and easing are held in coaxial spaced relation. 7

- In testimony whereof, We have hereunto signed our names at'BOyertOWn, Pennsylvania, this 18th day pf May, 1928. a

. THOMSON KING.

DANIEL G. BUR-KERT. 

